1 cup sugar
1 cup water
1 cup freshly squeezed juice from lemons/limes (I could only find medium sized lemons and slightly smaller than medium limes, so it took me about 6 lemons and 7 limes to do a double recipe. You can use the bottled juice and just get a few lemons for the zest and bowls)
2 teaspoons fine lemon zest
3. Once the mixture has thoroughly chilled, freeze in your ice cream maker according to the manufacturer's instructions.
4. Place sorbet in an airtight container and freeze until ready to serve.
5. In the mean time, between stirrings or whenever, scoop out the insides of the lemon halves and put in the freezer. When it is time to serve the sorbet (or an hour or two before serving time), scoop out the sorbet and fill the lemon half. You will have to mold the sorbet either with your hands or the spoon. I put on rubber gloves to do this so my hands wouldn't be as cold or as sticky.